# A line is parallel to the horizontal axis. The slope of the line is what?

Slopes are important concepts that can be used to extract various information about different curves. There are many interesting properties related to slopes. The basic formula for slope is perpendicular divided by the base. Let's explore one of those interesting properties about slopes.

## Answer: The slope of a horizontal line is always zero.

Let's understand the why of the solution.

**Explanation:**

We know that the formula for slope is the length of the perpendicular divided by the length of the base.

But for the case of a horizontal line, the length of the perpendicular is zero, which makes the numerator in the above formula zero.